1. Field of the Invention
Exemplary embodiments disclosed herein relate to oligomers and polymers and polymerizable compositions useful as optical materials and articles formed therefrom. As used herein, the term “optical materials” refers generally to substances which function to transmit, alter or control electromagnetic radiation in vacuum ultraviolet, ultraviolet, visible, near infrared, infrared, far infrared, and terahertz spectral regions. Optical materials may be articles that utilize the optical properties of the optical materials. Such articles may include monolithic or laminated structures, coatings, adhesives, fibers, faceplates, optical disks, filters, lenses, solar cell components, and LED optics components, to name a few.
Optical properties of interest may include transparency or transmission of radiation at the wavelength(s) of interest, refractive index, birefringence, dispersion, optical anisotropy, polarization, color stability, reflective or anti-reflective characteristics and the like, and the spectral dependency of such properties.
Additionally, certain other physical or chemical properties may be of interest in applications using optical materials. Some properties of interest include chemical (e.g., solvent) resistance, heat resistance, film-forming ability, fiber-forming ability, ease of polymerization, flexibility, gas barrier properties, surface flatness, geometrical stability, impact resistance, scratch and abrasion resistance, toughness, shrinkage, coefficient of thermal expansion, resistance to yellowing, dielectric constant, and the like.
2. Background
Historically, it has been known to use glass or transparent polymer materials such as polymethyl methacrylate (PMMA) and polycarbonate (PC). Although PMMA has excellent optical properties, its use may be limited because of low heat resistance resulting from a glass transition temperature (Tg) of about 100° C. PC, on the other hand, has a higher Tg (140° C.) but has poorer optical characteristics when compared to PMMA. Additionally, PC may exhibit low surface hardness causing susceptibility to scratching, low weatherability, and low moldability.
Certain co-inventors of the instant application are also inventors of the subject matter disclosed in published patent applications on improved methods of synthesis of methylene malonates, namely, WO 2012/054616 Synthesis of Methylene Malonates Substantially Free of Impurities, and WO 2012/054633 Synthesis of Methylene Malonates Using Rapid Recovery in the Presence of a Heat Transfer Agent. The synthesis procedures provided therein result in improved yields of heretofore-elusive high quality methylene malonates and other polymerizable compositions having the general formula (I):
wherein R and R′ may be the same or different and may represent nearly any substituent or side-chain.
Certain of these compounds may be amenable to chain-building and/or cross-linking polymerization by anionic or free radical initiation and have the potential to form the basis of a highly valuable and large-scale platform for the chemical synthesis and formulation of new chemical products.
Improvements in the performance of optical materials are continuously sought, especially in the fields of photonics, fiber optics, solar cells, automotive components, optical lenses, displays, windows, architectural glass, optical devices, optical substrates, optical coatings and adhesives. With the advent of improved synthesis processes, opportunities exist for new classes of commercially viable products, in particular, optical materials and their utilization in a variety of applications.